Diffusion transfer of dichroic iodine stain in vectograph production



155M961 m is SEARCH x9 awn- 99% March 7, 1957 J. MAHLER 3,307,946

DIFFUSION TRANSFER OF DICHROIC 101mm STAIN IN VECTOGRAPH PRODUCTION Filed May 9, 1965 Amaam INVENTOR JOSEPH MAH LE P ATTO NEY United States Patent 3,307,946 DIFFUSION TRANSFER OF DICHROIC IODINE STAIN IN VECTOGRAPH PRODUCTION Joseph Mahler, Fiskdale, Mass., assignor to American Uptieal Company, Southbridge, Mass., a voluntary association of Massachusetts Filed May 9, 1963, Ser. No. 279,263 4 Claims. (Cl. 96-29) This invention relates to vectographs and more particularly to a novel method of producing, on a transparent vectograph film, image information such as lines, letters, drawings or the like having self-contained light-polarization.

It is to be understood that the term vectograph, .as used herein, is directed more particularly to fihns, projection slides, test charts or the like having, on a clear colorless background, single, double and/ or stereoscopic light-polarizing image information or the reverse thereof hereinafter referred to as black and white vectographs. When stereoscopic image information is used, the images are arranged in accurately registered pairs in a conventional manner with their axes of polarization at 90 to each other so as to produce a three-dimensional effect when viewed through conventional light-polarizing analyzers.

The prime object, therefore, of the present invention is to provide a simple, novel and inexpensive method of producing black and white vectographs of the .above nature.

Another object is to provide a novel method of forming black and white vectographs of the above nature wherein standard and readily available materials are used.

Another object is to provide a novel vectograph printing process wherein the required steps of the process, including preparation of chemical formulas, exposure times or the like are not critical.

Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:

FIG. 1 is a fragmentary plan view of an exposed and developed conventional camera film having image information formed thereon in accordance with the invention and which will hereinafter be referred to as a master negative;

FIG. 2 is an enlarged fragmentary sectional view taken as on line 22 of FIG. 1;

FIG. 3 is a fragmentary plan view generally similar to FIG. 1 of a conventional vectograph film;

FIG. 4 is an enlarged fragmentary sectional view taken as on line 4-4 of FIG. 3;

FIG. 5 is a diagrammatic sectional view illustrating a a step of the method of the invention;

FIG. 6 is a view similar to FIG. 1 ofthe end product resulting from the method of the invention; and

FIG. 7 is a view generally similar to FIG. 6 of an end product resulting from a modification of the invention.

Referring more particularly to the drawings wherein like characters of reference designate like parts throughout the several views, there is shown in FIG. 1 what will be referred to hereinafter as a master negative film '10. This negative film is of a conventionally known type em bodying an emulsion containing uniformly distributed silver halides which is first exposed to form characters of the desired related shapes and sizes and which is thereafter developed in a conventional manner so as to produce a negative having transparent image information 11 thereon surrounded by a dark background of reduced metallic silver 12. A film of this nature which has produced excellent results is sold commercially under the trade name Kodalith by the Eastman Kodak Company, Rochester, New York.

3 ,307,946 Patented Mar. 7, 1967 In FIG. 3, there is shown a vectograph film 13 of the standard commercially available type which embodies an intermediate supporting sheet of transparent plastic material such as cellulose acetate butyrate 14 having laminated on the opposite sides thereof layers '15 and 15', of a water absorptive material such as polyvinyl alcohol whose molecules have been oriented in a given direction by stretching said layers or by the use of any other known means. The direction of orientation of molecules of the layer 15 is illustrated by the arrow 16 in FIGS. 3 and 6.

In carrying out the method of the invention, one side 15 of the standard vectograph film 13 is first stained as illustrated by the horizontal lines 19 in FIG. 4. This staining may be accomplished by brushing the staining solution on the layer or by any other known manner. The preferred staining solution comprises 100 ccs. water, 10 to 20 grams sodium sulphate, and from 5 to 10 cos. of a stock solution consisting of 100 ccs. water, 30 to 50 grams potassium iodide and from 5 to 10 grams iodine crystals. The time interval for staining is from between 10 to 60 seconds. The reason for subjecting the layer 15 of the vectograph film 13 to a staining solution, "as specified above, is to render the oriented molecules dichroic and light-polarizing and the sodium sulphate of the staining solution functions to restrict the penetration of the staining solution in the polyvinyl alcohol layer 15 during the time interval in which the film is subjected to the staining solution. This is to insure that the stain only superfically penetrates the layer 15 as will be described more in detail hereinafter.

In further carrying out the method of the invention, the master negative film 10 is first placed in plain water for at least two minutes to soften the same. The master negative film and the stained vectograph film 13 are then placed in superimposed relation with each other with the metallic silver side of the master negative film 12 engaging the stained layer 15, as shown in FIG. 5. The superimposed films are placed on a stable support 17 and are forced into intimate relation with each other by any suitable means such as a rubber roller or the like 18, for a time interval of about two minutes or for a period sufficient to permit the reduced metallic silver to bleach out the staining solution where engaged thereby. The reasons for the use of sodium sulphate, which permits only a superficial staining of the vectograph film, is to insure a more complete bleaching action. This causes the stain, as shown at 20, to remain in the layer 15 only throughout the confines of the transparent image information portions 11 of the master negative film or only throughout the areas thereof where there is no metallic silver. This, therefore, renders the background area 21 of the resultant product 22, such as a film, projection slide, test chart or the like to be rendered isotropic without destroying the dichroic light-polarizing properties of the resultant image information 23 which, during the printing step illustrated in FIG. 5, assume the shapes of the transparent image areas 11 of the master negative film. The direction or axis of polarization of said image information 23 is indicated by the arrow 16. In this instance, the layer 15' is not stained and will, therefore, be clear and of a transparent isotropic nature.

If it is desired to produce separately visible image information on the opposite side 15' of the vectograph film 13, the same steps of the process as described above are repeated. It is further to be noted that the axis of polarization of the image information on the second side 15' is disposed at an angle of relative to the direction of polarization of the first side, as indicated by the arrow 25, so that when the resultant product is viewed through spaced conventional light-polarizing analyzers, the image information on the opposite sides of the film will be separately visible only to the respective eyes. This is due to the fact that the analyzers have their axes of polarization at 90 to each other similar to the axes of polarization of the respective image information. It is to be understood, however, that while the steps of the process are the same as for the printing of the first side, a difierent master neg-ative film having the desired image information for said side is required.

If a three-dimensional efifect is desired, similarly formed image information 23 and 24 are printed on the opposite sides of the vectograph film 13 with the exception that, in this instance, the image information is arranged in accurately registered pairs, as shown in FIG. 7, one on each side of the vectograph film 13 and with the axis of polarization of the image information 23 being disposed in a side of the vectograph film 13 and with the axis of polarization of the other of said image information being disposed in a direction indicated by the arrow 25.

Here again, the end product is viewed through conventional light-polarizing analyzers, such as described above, whereby the respective image information will be visible only to the respective eyes of the individual viewing same but will further have a three-dimensional appearance.

Directly subsequent to the printing step such as illustrated in FIG. 5 or to each of the printing steps for the opposite sides of the vectograph 13, the master negative film is removed from the vectograph film and the film is thereafter imbibed in a fixing solution consisting of approximately 5 grams boric acid, 0.5 to 1 gram potassium iodide, and 0.1 to 0.5 gram borax in 100 ccs. water to stabilize the film. It is to be understood that any excess water or staining solution on the respective master negative films and the vectograph films 11 is removed prior to placing them in superimposed relation to each other, as illustrated in FIG. 5.

The result-ant products illustrated in FIGS. 6 and 7, preferably embody image configurations having substantially uniform light-polarization surrounded by a substantially clear and colorless isotropic background.

It is pointed out that while the image information is indicated as being formed with solid uniform density, they may be formed so as to have the appearance of images formed by a known so-called half-tone printing technique.

While it has been shown and described above that the process is carried out by the use of a so-oalled master negative film, it is apparent that a positive master film or conventional photographic print having portions of a side area thereof of reduced silver and other portions thereof free from said reduced silver might be employed to obtain end products which are the reverse of those shown in FIGS. 6 and 7.

The steps of the process are the same with the exception that the master negative film resulting from said initial exposure and development is utilized in producing the master positive film wherein the image information of said master positive film will be of reduced metallic silver and will be surrounded by a clear and isotropic background.

In this instance, the end products, such as shown in FIGS. 6 and 7, instead of having the areas of the image information stained and light-polarizing, they will be clear and isotropic and will be surrounded by a stained and light-polarizing background.

In instances when both sides of the vectograph are used, the axes of polarization of the backgrounds will be at 90 to each other. This, therefore, produces the reverse of the first-described process. The images, however, may similarly be rendered separately visible to the respective eyes by the use of conventional analyzers which, in this instance, neutralize the backgrounds instead of the image information.

From the foregoing, it will be seen that a simple, eflicient and economical method of forming printed vectographs has been provided. However, it is to be understood that many changes may be made in the steps of the method and chemical compositions used without departing from the spirit of the invention as expressed in the accompanying claims and the invention, therefore, is not to be limited to the exact matters shown and described as the preferred matters have been given only by way of illustration.

Having described my invention, I claim:

1. The method of transferring image information onto a transparent vectograph film member from a conventional photographic master member including a backing support having on one side thereof a continuous layer of water absorptive material containing fully developed image means and background means, one of said means embodying reduced metallic silver and the other of said means being free from said reduced metallic silver, said vectograph member embodying a support of transparent material having a continuous layer of water absorptive material laminated to at least one side thereof with its molecules oriented in a given direction; said method comprising the steps of applying to said continuous layer of water absorptive material of said vectograph member an aqueous staining solution containing a dichroic iodine stain capable of being bleached by reduced metallic silver, wetting said photographic master member sufiiciently to soften same, placing said water absorptive layers of said master member and vectograph member in direct contact with each other and retaining the same in said relationship for a time interval sufiicient to cause said reduced metallic silver in said master member to elim inate by bleaching the presence of dichroism of said stain in said vectograph member throughout areas where said metallic silver contacts said vectograph member, separating said master and vectograph members and subjecting said vectograph member to a fixing solution to stabilize same.

2. The method as recited in claim 1 wherein said aqueous staining solution comprises the equivalent of ccs. water and from S to 10 ccs. of a stock solution consisting of 100 ccs. water, 30 to 50 grams potassium iodide and 5 to 10 grams iodine crystals.

3. The method as recited in claim 2 wherein said vectograph member is subjected to said aqueous staining solution for a period of from 10 to 60 seconds.

4. The method as recited in claim 1 wherein said vectograph member has a layer of said molecularly oriented water absorptive material laminated to each of its opposite sides and said steps of said method are applied to both of said sides of said vectograph member.

References Cited by the Examiner UNITED STATES PATENTS 2,299,906 10/1942 Land 96-35 2,346,775 5/1944 Mahler 101149.1 2,409,959 10/ 1946 Ryan et al. 9629 2,445,581 7/1948 Land 9629 2,997,390 8/1961 Land 9629 OTHER REFERENCES Friedman: History of Color Photography, 1944, 343, -434 pub. 1944, The Amer. Phot. Pub. Co., Boston,

ass.

Judge: Stereoscopic Photography, pp. 307-310, published by Chapman and Hall, 1950, London, Eng.

Mees: The Theory of the Photographic Process, pp. 576-578, 1942 by the MacMillan Co., New York, NY.

NORMAN G. TORCHIN, Primary Examiner.

DONALD LEVY, Examiner. 

1. THE METHOD OF TRANSFERRING IMAGE INFORMATION ONTO A TRANSPARENT VECTOGRAPH FILM MEMBER FROM A CONVENTIONAL PHOTOGRAPHIC MASTER MEMBER INCLUDING A BACKING SUPPORT HAVING ON ONE SIDE THEREOF A CONTINUOUS LAYER OF WATER ABSORPTIVE MATERIAL CONTAINING FULLY DEVELOPED IMAGE MEANS AND BACKGROUND MEANS, ONE OF SAID MEANS EMBODYING REDUCED METALLIC SILVER AND THE OTHER OF SAID MEANS BEING FREE FROM SAID REDUCED METALLIC SILVER, SAID VECTOGRAPH MEMBER EMBODYING A SUPPORT OF TRANSPARENT MATERIAL HAVING A CONTINUOUS LAYER OF WATER ABSORPTIVE MATERIAL LAMINATED TO AT LEAST ONE SIDE THEREOF WITH ITS MOLECULES ORIENTED IN A GIVEN DIRECTION; SAID METHOD COMPRISING THE STEPS OF APPLYING TO SAID CONTINUOUS LAYER OF WATER ABSORPTIVE MATERIAL OF SAID VECTOGRAPH MEMBER AN AQUEOUS STAINING SOLUTION CONTAINING A DICHROIC IODINE STAIN CAPABLE OF BEING BLEACHED BY REDUCED METALLIC SILVER, WETTING SAID PHOTGRAPHIC MASTER MEMBER SUFFICIENTLY TO SOFTEN SAME, PLACING SAID WATER ABSORPTIVE LAYERS OF SAID MASTER MEMBER AND VECTOGRAPH MEMBER IN DIRECT CONTACT WITH EACH OTHER AND RETAINING THE SAME IN SAID RELATIONSHIP FOR A TIME INTERVAL SUFFICIENT TO CAUSE SAID REDUCED METALLIC SILVER IN SAID MASTER MEMBER TO ELIMINATE BY BLEACHING THE PRESENCE OF DICHROISM OF SAID STAIN IN SAID VECTOGRAPH MEMBER THROUGHOUT AREAS WHERE SAID METALLIC SILVER CONTACTS SAID VECTOGRAPH MEMBER, SEPARATING SAID MASTER AND VECTOGRAPH MEMBERS AND SUBJECING SAID VECTOGRAPH TO A FIXING SOLUTION TO STABILIZE SAME. 